The common ancestor among mouse deer (also known as chevrotains) and whales can be traced back to a group of mammals called cetaceomorpha. This group includes whales, dolphins, and their extinct ancestors that lived on land. Around 50 million years ago, some of these early cetaceans started adapting to aquatic life, eventually evolving into the whales we know today. Mouse deer, on the other hand, are part of the artiodactyl order, which includes even-toed ungulates like deer, cows, and pigs. These two groups diverged from a common ancestor much earlier, around 60-70 million years ago.
